Mitral valve prolapse (MVP) is among the most common heart conditions, but it remains something of a puzzle. Although MVP affects about 2% of the population, the cause is unknown. MVP often occurs in people who have no other heart problems, and the condition may be inherited.

The mitral valve is located in the heart between the upper-left chamber (the left atrium) and the lower-left chamber (the left ventricle). The mitral valve consists of two flaps called leaflets.

Normally, the leaflets open and shut in coordinated fashion to allow blood to flow in one direction—from the atrium to the ventricle.

But in patients with MVP, one or both of the leaflets are enlarged, and the leaflets' supporting muscles are too long. Instead of closing evenly, one or both of the leaflets collapse or bulge back into the atrium, sometimes allowing small amounts of blood to flow back into the atrium. By listening to your heart with a stethoscope, your doctor may hear a "clicking" sound caused by the flapping of the leaflets.

What are the risks of MVP?

Sometimes, MVP leads to a condition known as mitral regurgitation or mitral insufficiency. This means a large amount of blood is leaking backward through the defective valve. Mitral regurgitation can lead to the thickening or enlargement of the heart wall, caused by the extra pumping the heart must do to make up for the backflow of blood. It sometimes causes people to feel tired or short of breath. Mitral regurgitation can usually be treated with medicines, but some people need surgery to repair or replace the defective valve.

How is MVP treated?

Most of the time, MVP is not a serious condition, even though some patients report palpitations or sharp chest pains. Most patients do not need treatment. If you have MVP, let your doctor know if you are going to have dental or general surgery, so he or she can follow current guidelines about taking antibiotics prior to surgery.

MVP should not stop a person from living a productive life, but it should be monitored regularly by a doctor.